A vertical compressor which is used in an air conditioner is provided with a plurality of elastic supporting members such as rubber or coil-springs interposed between the compressor and a base plate of an outdoor unit with the aim of preventing vibrations of the compressor from being directly transmitted to the outdoor unit of the air conditioner. Specifically, one end of the elastic supporting member is fitted into a locking hole of an attachment leg which is fixed to a bottom portion of a compressor housing, and the other end of the elastic supporting member is installed on the base plate of the outdoor unit. By screwing a locking nut onto a male screw which is provided on the tip of a locking bolt which passes through the base plate, the elastic supporting member, and the locking hole of the attachment leg, the compressor is elastically supported on the base plate of the outdoor unit. The movement of the compressor in the vertical direction is restricted to a range of a gap between the elastic supporting member and the bottom end of the locking nut.
With the aim of rendering the attachment space of the compressor on the base plate of the outdoor unit as small as possible, the plurality of elastic supporting members (and the locking holes of the attachment legs) which support the compressor are concentric with the compressor housing, are disposed on the outside in the radial direction of the compressor housing so as to screw the locking nuts from above using a handled box wrench, and three of the elastic supporting members (and the locking holes of the attachment legs) are generally used with the aim of reducing the attachment space and the cost.
In the attachment structure of the compressor described above, with the aim of preventing the compressor from becoming inclined to an accumulator side due to the weight of the accumulator which is fixed to the side portion of the compressor housing, for example, JP-A-2009-162120 describes an attachment structure in which there are provided a plurality of attachment mechanisms including an attachment leg which is fixed to the compressor, a supporting portion which is provided on a frame to which the compressor is attached, and an elastic supporting member which is disposed between the supporting portion and the attachment leg. The attachment mechanisms include a plurality of types of attachment mechanisms in which the configuration of one or more of the attachment leg, the supporting portion, and the elastic supporting member differs from that of the other attachment mechanisms. Specifically, attachment structures are described in which a height direction spacer is inserted in a portion of the elastic supporting members, the hardness of a portion of the elastic supporting members is changed, the positions of the plurality of elastic supporting members are rendered at an unequal pitch, or the like.
In recent years, technology is improving, and compressors have a tendency toward increased intake capacities while maintaining an equal size and mass of a compressor housing. However, if the intake capacity is increased, the compression load increases proportionally. Therefore, fluctuations in compression torque in a single rotation of a piston also increase proportionally. Accordingly, if the mass of the entire compressor is equal, since the fluctuation in compression torque to mass is increased, the vibration in the rotation direction centered on the housing center of the compressor housing increases.
In a state in which the compressor is installed in the outdoor unit of the air conditioner, the compressor is supported by not only the plurality of elastic supporting members, but also inlet-side piping and discharge-side piping which are connected to the compressor. Accordingly, if the vibration of the compressor increases, in a case in which the compressor is installed in the outdoor unit, there are problems in that the vibration of the piping which is connected to the compressor increases, the piping comes into contact with the housing of the outdoor unit and becomes a cause of noise, and further, that the piping stress exceeds a permitted value and the piping breaks.
Of the piping which is connected to the compressor, since the volumetric flow rate of refrigerant flowing inside the inlet-side piping is greater than that of the discharge-side piping, it is necessary to increase the diameter of the inlet-side piping. However, if the diameter is large, since the rigidity increases and it becomes difficult to absorb the vibration with the piping itself, there is a problem in that the vibration which is transmitted to the inlet-side piping, in particular, increases.
In JP-A-2009-162120, although a solution to the inclination of the compressor is proposed, there is no description of suppressing the vibration caused by fluctuation in the torque of the compressor. Bestowing rigidity on the elastic supporting member which supports the compressor using a method such as increasing the hardness of the elastic supporting member and attaching the compressor to the base plate of the outdoor unit are proposed with the aim of suppressing the inclination of the compressor. According to this method, an effect of suppressing the vibration amplitude of the compressor may be obtained. However, with this method, there are problems in that the vibration is more easily transmitted to the base plate of the outdoor unit, and the noise caused by the vibration of the base plate increases.